Your network contains two Active Directory forests named Contoso and Nwtraders. The
Contoso forest contains Exchange Server 2003 Service Pack 2 (SP2) servers.
The Nwtraders forest contains Exchange Server 2010 Service Pack 1 (SP1) servers.
You need to move all mailboxes from Contoso to Nwtraders.
What should you do from the Nwtraders forest?

A.
Create a linked mailbox for each mailbox in Contoso. Run the Move-Mailbox cmdlet.

B.
Create a shared mailbox for each mailbox in Contoso. Run the New-MoveRequest
cmdlet.

C.
Create a mail enabled contact for each mailbox in Contoso. Run the Move-Mailbox
cmdlet.

D.
Create a mail enabled user for each mailbox in Contoso. Run the New-MoveRequest
cmdlet.

Explanation:
Microsoft Exchange Server 2010 supports remote mailbox moves via the New-MoveRequest
cmdlet. To move a mailbox from an Exchange Server 2010, Exchange Server 2007, or
Exchange Server 2003 forest to another Exchange 2010 forest, the Exchange 2010 target
forest must contain a valid mail-enabled user with a specified set of Active Directory
attributes. (Exchange 2010 doesn’t support moving an Exchange 2000 Server mailbox.)
If there is at least one Exchange 2010 Client Access server deployed in the forest, the forest
is considered an Exchange 2010 forest.
http://technet.microsoft.com/en-us/library/ee633491.aspx